Employees calling and texting with business questions on a Saturday afternoon.

Customers commenting 24/7 on sites such as Yelp and Facebook.

There is little time for a business owner to turn off, and turn away, from work duties.

Entrepreneurship can be a rewarding, fulfilling — and all-encompassing — career path. If not kept in check, working too hard for too long can take a toll on a business owner's health, as well as affect his or her relationships with others.

Entrepreneurs who put an excessive focus on business can inadvertently damage relationships with friends and family, as well as burn themselves out. In addition, those who answer e-mails and take calls during non-traditional business hours may broadcast the message that they are available to work day and night.

"If you're doing too much work, you might be creating false expectations about what you can do," she says.

Recent surveys show that small-business owners are toiling hard.

Nearly 4 in 10 are working more hours per week than they were five years ago, according to a survey from business management software provider Sage. Four in 10 are taking significantly or somewhat less vacation time compared with five years ago.

Slightly fewer than half of small-business owners planned to take a vacation of at least one week this summer, down from 54% in 2012, according to the American Express OPEN Small Business Vacation Monitor survey from earlier this year.

This summer, business owner Ami Kassar felt the physical ramifications that can arise if an entrepreneur takes on too much. He felt dizzy and lightheaded, and headed to the emergency room. There was no definite diagnosis of what caused his symptoms, but he thinks stress was the culprit.

"Growth brings stress," says Kassar, CEO of MultiFunding, a firm that helps small-business owners figure out the best loan and working capital options.

As for his ailments, "I think I just fried my motherboard," he says. With too much work and not enough maintenance, devices such as laptops "can eventually fry out," he says, "and if we're not careful, we can do that, too."

He made some adjustments to get on a better track, such as delegating more work and unsubscribing from unnecessary e-mails that cluttered up his inbox.

He also "listens to his body" a bit more and knows when he should take some downtime or to go to bed.

Canada also offers this overall advice to overtaxed entrepreneurs who have limited resources: "Figure out what is important, and say no to everything else," he says. Focus on areas "that are going to have the most impact."

He has the same philosophy for the personal life side of things. "The relationships that matter should be attended to first and foremost," he says.